define html and css code example

Example 1: css in html

<!-- EXAMPLE -->
<div class="your_class" style="display:none">

<!--[SYNTAX: style="<CSS-code>"] -->

Example 2: how to use css

<link rel="stylesheet" href="stylesheet.css">
<div class="mydiv"></div>
<style>
.mydiv {
background-color: /*Color*/;
color: /*Another color*/;
}
</style>